Downregulation of SPARC Expression Inhibits the Invasion of Human Trophoblast Cells In Vitro

Abstract

Successful pregnancy depends on the precise regulation of extravilloustrophoblast (EVT) invasion into the uterine decidua. SPARC (secreted protein acidic and rich in cysteine) is a matricellular glycoprotein that plays critical roles in the pathologies associated with obesity and diabetes, as well as tumorigenesis. The objective of this study was to investigate the role of SPARC in the process of trophoblast invasion which shares many similarities with tumor cell invasion. By Western blot, higher expression of SPARC was observed in mouse brain, ovary and uterus compared to other mouse tissues. Immunohistochemistry analysis revealed a spatio-temporal expression of SPARC in mouse uterus in the periimplantation period. At the implantation site of d8 pregnancy, SPARC mainly accumulated in the secondary decidua zone (SDZ), trophoblast cells and blastocyst. The expression of SPARC was also detected in human placental villi and trophoblast cell lines. In a Matrigel invasion assay, we found SPARC-specific RNA interference significantly reduced the invasion of human extravilloustrophoblast HTR8/SVneo cells. Microarray analysis revealed that SPARC depletion upregulated the expression of interleukin 11 (IL11), KISS1, insulin-like growth factor binding protein 4 (IGFBP4), collagen type I alpha 1 (COLIA1), matrix metallopeptidase 9 (MMP9), and downregulated the expression of the alpha polypeptide of chorionic gonadotropin (CGA), MMP1, gap junction protein alpha 1 (GJA1), et al. The gene array result was further validated by qRT-PCR and Western blot. The present data indicate that SPARC may play an important role in the regulation of normal placentation by promoting the invasion of trophoblast cells into the uterine decidua.

Bioinformatics Analysis of Choriocarcinoma-Related MicroRNA-Transcription Factor-Target Gene Regulatory Networks and Validation of Key miRNAs

“… 36 Jiang et al showed that SPARC depletion upregulated the expression of IGFBP4, which promoted the invasion of JEG-3. 29 The above results were consistent with our study, strongly indicating that hub genes mostly participated in tumour proliferation and invasion.…”

“… 28 Jiang et al found that the mRNA and protein expression of SPARC was downregulated in JEG-3 cells compared with HTR-8/SVneo cells. 29 Furthermore, miRNAs in cancer were the primary pathway for DEG enrichment. This result suggested that miRNAs may play a vital role in mediating choriocarcinoma progression.…”

Elevated Plasma SPARC Levels Are Associated with Insulin Resistance, Dyslipidemia, and Inflammation in Gestational Diabetes Mellitus

“…A recent study showed that human placenta villi could express and secrete SPARC [27], suggesting that levels of SPARC may be affected by gestational age. However, in our study the subjects in GDM group and control group had similar gestational age, around 26 weeks of gestation and it has been shown that circulating levels of SPARC mainly come from adipose tissue [11], therefore, the differences in circulating levels of SPARC in GDM patients and controls may not be caused by gestational age.…”

“…So far there are limited studies on SPARC and diabetic subjects, and the findings are consistent with our results: levels of SPARC are significantly elevated in T2DM patients compared with normal controls in Chinese and Japanese populations [14] , [26] . A recent study showed that human placenta villi could express and secrete SPARC [27] , suggesting that levels of SPARC may be affected by gestational age. However, in our study the subjects in GDM group and control group had similar gestational age, around 26 weeks of gestation and it has been shown that circulating levels of SPARC mainly come from adipose tissue [11] , therefore, the differences in circulating levels of SPARC in GDM patients and controls may not be caused by gestational age.…”

Diverse Roles of Prostaglandins in Blastocyst Implantation

“…Following blastocyst adhesion, trophoblast cells differentiate and acquire the invasive phenotype [ 154 ]. The role of PGs in facilitating trophoblast invasion is largely unknown; however, several evidences indicate its involvement in this process.…”